Great Wall/Great Spy/Infiltration/Tech Stealing Gambit

[Thrak]

Read about this somewhere, tried it last night in a multiplayer (with some AI) and it's insanely overpowered imo.

Basically you do the following:

Tech to Masonry
Build Great Wall
Wait for great spy
Send great spy to a powerful civ and infiltrate (for 3k esp points in my case)
In the meantime tech to alphabet
Build a few spies (3x or so should do)
Steal all techs

This is crazy - for the investment of Great Wall and 3x spies, you can effectively beeline your own research and backfill from the target civ.

Worked for me with Phi and also grabbing bronzeworking to chop in the GW.

Due for a nerf?

[LDiCesare]

This works but for me it had the side effect of giving too many great spy points in my capital, which ended up generating spies instead of scientists against the odds. And later on, scientists, engineers and merchants are more useful than spies imo.
You do steal a lot of techs early on with this technique. Probably the quantity of spy points generated by the great spy should vary with time (less early in game, much more late game). After all, lightbulbs have very different costs depending whether your GP used it in 1000BC or 1000 AD.